1. Field of the Invention
This invention relates generally to the field of disk drives for data storage units used in data processing systems, and more particularly to a release mechanism for quickly and easily releasing the head and disk housing assembly thereof, to facilitate its insertion and removal.
2. Description of the Prior Art
Data processing systems typically include one or more mass data storage units in which data can be written on or retrieved from a magnetic medium. In modern data storage units, the magnetic medium typically may be deposited on and supported by an annular substrate such as aluminum. This disk is mounted in a drive in which it is rapidly rotated about its axis. The drive includes read/write heads which can be moved by an actuator in the drive across the disk surface to permit any one of a series of concentric annular data tracks to be accessed, the tracks being disposed on the substrate at differing radii. A drive may contain either a single disk or several disks stacked in spaced apart relation on a common spindle.
It has been an objective in recent years to increase the amount of data that can be stored on each disk, as well as the density at which the data is stored on the medium. This has necessitated an improvement not only in the magnetic medium itself, but also in the techniques used in manufacturing the drive, as rigid mechanical tolerances must be maintained to ensure that the read/write heads maintain the proper spacings over the disks. Furthermore, since the data is stored magnetically, the disk typically would attract dust from the surrounding air. If dust is permitted to accumulate on the disk surface, the accumulated dust would increase the height the read/write head must maintain above the disk, requiring the use of higher recording flux densities and reducing the available storage densities. The dust on the surface would also cause excessive wear on the head and slider.
To increase the reliability of the high-density mass storage disk, the so-called "Winchester"-type disk drives were developed in which the disks and the read/write heads and their actuating assemblies are all mounted in a housing assembly which is sealed to keep dust away from the disks. Filtered air may be directed over the annular disk surfaces to guard against the accumulation on the disks of dust which may seep into the housing. In prior art "Winchester"-type disk drives, as exemplified in U.S. Pat. No. 4,054,931 issued Oct. 18, 1977, the disk housing assembly comprises a heavy slab-like metal base plate and a separate cover, of lightweight material such as plastic, which completes and seals the housing. A gasket may be used between the base and the cover to enhance the sealing. The base plate is usually larger than the cover, but the cover extends over the portion of the base plate necessary to enclose the disks and the head actuator.
The disk housing assembly is mounted in the disk drive cabinet, which includes a drive motor for rotating the disks, typically through a belt which cooperates with a disk spindle pulley projecting through the bottom of the housing. The drive also typically includes power supplies for driving the motor and drive control logic circuitry to facilitate reading and writing the data from and onto the disks.
Heretofore, it has been cumbersome and time-consuming to remove the disks or the disk housing assembly from a "Winchester"-type disk drive. Such removal may be necessary when, for instance, the disk drive belt breaks or if a serious problem arises with the disks, heads, head, actuator or other elements of the drive. Several hours of service and "down" time may be required merely to remove and replace a disk housing assembly in prior art "Winchester" disk drives.
This invention provides a release mechanism whereby the complete disk housing assembly of a "Winchester" disk drive can be easily disengaged from and engaged to the drive in just a few minutes, substantially reducing the disk drive down time and the service expense.